Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Response to Arguments
Applicant’s arguments, see Remarks page 5, filed 24 April 2026, with respect to the rejections under 112(b) have been fully considered and are persuasive. The 112(b) rejections of the claims have been withdrawn.
Applicant’s arguments, see Remarks page 7, filed 24 April 2026, with respect to the rejection of claim 1 under 35 USC 103 have been fully considered and are persuasive in light of the amendments to the claims. Therefore, the rejection has been withdrawn. However, upon further consideration, a new ground of rejection is made in view of Weitz et al.
Applicant’s arguments, see Remarks page 8, filed 24 April 2026, with respect to the combination of Koksal et al in view Lang with the reference Ogawa et al have been fully considered but are not persuasive.
Ultimately, one of ordinary skill in the art of acoustic transducers, seeking to transfer acoustic vibrations into a substance, would look at other devices which generate acoustic energy and transfer that to a substrate. One of ordinary skill in the art would be aware that sound waves bounce and reflect—such teaching is present in the primary reference of Koksal et al ([0003]). Such a person, faced with these teachings, would ask the question, how can I make sure the acoustic energy I am generating is transferred correctly to my substrate of interest? What techniques are present in other devices?
Ogawa et al teaches the generation of acoustic waves via a transducer which need to be coupled efficiently to a substrate. Ogawa et al teaches that the sound waves may proceed through several layers before arriving at the substrate. Ogawa et al teaches that the several layers which a sound wave proceeds through may be matched in a stepwise manner to the acoustic impedance of the substrate, in order to minimize reflections.
It is this technique in Ogawa et al, this use of multiple layers between a transducer and a substrate, designed to propagate sound waves, formed with a stepwise change in impedance to prevent the unwanted reflection of sound waves, that one of ordinary skill in the art would be motivated to apply to other devices. Accordingly, the examiner believes the combination of Ogawa et al is proper. The rejections in view of Ogawa et al are maintained.
Status of Claims
Applicant's amendments to the claims filed 24 April 2026 have been entered. Applicant's remarks filed 24 April 2026 are acknowledged.
Claims 1, 4, and 6 are in status “Currently amended.” Claims 2, 3, 5, 8, 10 – 12, and 21 – 23 are in status “Original” or “Previously presented.” Claims 24 – 29 are new. Claims 7, 9, and 13 – 20 are cancelled.
Claim Rejections - 35 USC § 103
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claims 1-10, 22, and 23 are rejected under 35 U.S.C. 103 as being unpatentable over Koksal et al (US 20180214874 A1, cited on PTO-892 form submitted 12 May 2025) in view of Lang (DE 102012207873 A1, cited on PTO-892 form submitted 12 May 2025 and attached alongside that submission) in view of Ogawa et al (US 20050261590 A1), and further in view of Weitz et al (US 20180257076 A1).
With regards to claim 1, Koksal et al teaches;
The claimed “a microfluidic chip including a microchannel” has been read on the taught (Figure 5, microfluidic chip 320, microfluidic flow channels 330; abstract, line 1, “A microfluidic chip assembly having a plurality of microfluidic flow channels is provided.”);
The claimed “an interdigital transducer (IDT) including electrodes and piezoelectric substrate” has been read on the taught ([0006], “A surface acoustic wave may be generated using an inter-digitated transducer (IDT) supported by a piezoelectric substrate. The transducer may be formed of two comb-shaped electrodes having interlocking teeth or fingers.”);
Koksal et al additionally teaches;
“A layer configured to transmit acoustic waves, disposed between the microfluidic chip and the piezoelectric substrate” has been read on the taught (Figure 8D, coupling agent 367, cover layer 363, piezoelectric substrate 364, upper substrate 362, channel 330; [0112], “…the IDT 512 may be patterned on piezoelectric substrate 364 that may indirectly contact cover substrate 363 of the channel 330 through a coupling agent 367.”; Coupling agent 367 reads on one layer configured to transmit acoustic waves. Piezoelectric substrate 364 reads on the piezoelectric substrate. The upper substrate 362 defining a channel 330 reads on the microfluidic chip.);
“The interdigital transducer generating surface acoustic waves that couple into the microfluidic channel through the layer” has been read on the taught (paragraph 0152, “Supplying a driving frequency to IDT 512 causes the IDT 512 to generate a surface acoustic wave that travels along the length of the acoustically-transmissive material band 612, into the coupling element 367, into the superstrate 366 and into the microfluidic channel 330.”);
Koksal et al additionally teaches that it is desirable to efficiently transfer acoustic energy to the microfluidic chip, as read on the taught ([0137], “Various coupling elements 367 and materials may be used to couple the surface acoustic wave generator assembly 505 to the microfluidic chip 320 and to efficiently transmit the acoustic energy.”);
However, Koksal et al does not explicitly disclose a plurality of layers disposed between the microfluidic chip and the piezoelectric substrate, each of the plurality of layers having a different acoustic impedance property, the plurality of layers having a thickness in a range from 10 micrometers to 250 micrometers, or the plurality of layers overlying a portion of the electrodes of the IDT such that surrounding air is disposed over another portion of the electrodes of the IDT.
In the analogous art of acoustic devices incorporating piezoelectric transducers, Lang teaches;
“A piezoelectric transducer element” has been read on the taught (Figure 1, piezoelectric transducer element 114; [0002], “Ultrasonic transducers generally have at least one electromechanical transducer element, in particular a piezoelectric transducer element. An electromechanical transducer element is here as well as hereinafter understood to mean an element which is set up to convert electrical signals into acoustic signals or vice versa.”);
The claimed “a plurality of layers configured to transmit acoustic waves” has been read on the taught (Figure 1, matching body 116, sealing layer 124; [0003], “Furthermore, it is known from the prior art that at least one matching body can be used to improve a coupling of the acoustic signals between the electromechanical transducer element and the fluid medium.”; [0008], “In the proposed method, a cross-linkable sealing material is applied to the matching body on a side facing the fluid medium, for example on at least one emitting surface and / or coupling surface of the ultrasonic transducer, and crosslinked.”; Matching body 116 and sealing layer 124 read on a plurality of layers configured to transmit acoustic waves);
The claimed “the plurality of layers having a thickness in a range from 10 micrometers to 250 micrometers” has been read on the taught ([0021], “For example, the sealing material on the matching body can have a layer thickness of 5 to 200 micrometers, in particular 10 micrometers to 100 micrometers…”).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the microfluidic system including a layer for transmitting surface acoustic waves as taught by Koksal et al with the plurality of layers having a thickness in a range from 10 to 200 micrometers as taught by Lang, for the benefit of providing a suitable thick protective layer which can prevent undesirable substances from filling adjacent porous layers ([0004], “In particular, when using ultrasonic transducers with open-pore matching bodies, a problem is that the pores on a surface of the matching body, in particular towards the fluid medium, during production, storage, handling or during use of the ultrasonic transducer completely or partially with adjacent substances can fill.”; [0021], “The proposed method and the proposed ultrasonic transducer have many advantages over known methods of the type mentioned… In particular, the crosslinking of the sealing material during application and/or immediately after application […] allow comparatively high layer thicknesses of one or more layers of the sealing material… In contrast, known coating methods […] have the disadvantage that with such methods usually only insufficient layer thicknesses are possible or that coarse-pored structures only insufficiently closed…”).
However, Koksal et al in view of Lang does not explicitly disclose each of the plurality of layers having a different acoustic impedance property or the plurality of layers overlying a portion of the electrodes of the IDT such that surrounding air is disposed over another portion of the electrodes of the IDT.
In the analogous art of devices designed to transmit acoustic energy, Ogawa et al teaches;
The claimed “a plurality of layers configured to transmit acoustic waves” has been read on the taught ([0081], “An acoustic matching unit 25A is provided on an upper surface of the piezoelectric element unit 12A. This acoustic matching unit 25A includes plural acoustic matching layers 17A formed in a strip shape.”);
The claimed “each of the plurality of layers having a different acoustic impedance property,” has been read on the taught ([0082], “…the acoustic matching layers 17A include first acoustic matching layers 18A (conductive members) and second acoustic matching layers 19A, which are made of different materials, such that the acoustic impedances change stepwise from the piezoelectric elements 15A toward the human body.”).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the device including a coupling layer as taught by Koksal et al in view of Lang with the plurality of layers, each having a different acoustic impedance as taught by Ogawa et al. According to MPEP 2143(I)(C), use of a known technique to improve similar devices in the same way may be prima facie obvious. In the case of the instant invention, the prior art of Koksal et al contains a “base” device of an acoustic wave generator with an impedance matching layer coupling to a test surface. The prior art of Ogawa et al contains a “comparable” device which has been improved in the same way as the invention; an acoustic wave generator that has been improved with multiple impedance matching layers coupling towards a testing surface, each layer having a different acoustic impedance. One of ordinary skill in the art could have applied the technique of multiple layers in the same way to the “base” device, for the predictable result of more efficiently transmitting acoustic waves from the starting substrate to the testing surface.
However, Koksal et al in view of Lang et al in view of Ogawa et al does not explicitly disclose the plurality of layers overlying a portion of the electrodes of the IDT such that surrounding air is disposed over another portion of the electrodes of the IDT.
In the analogous art of surface acoustic wave devices, Weitz et al teaches;
The claimed “the plurality of layers overlying a portion of the electrodes of the IDT such that surrounding air is disposed over another portion of the electrodes of the IDT” has been read on the taught ([0085], “The fingers of the IDT are situated beneath an air gap, to prevent the power carried by the SAW from leaking into the device prematurely.”)
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the layers atop the IDT as taught by Koksal et al in view of Lang and further in view of Ogawa with the air gap as taught by Weitz et al, for the predictable benefit of preventing ([0085], “The fingers of the IDT are situated beneath an air gap, to prevent the power carried by the SAW from leaking into the device prematurely.”).
With regards to claim 2, the system of claim 1 is obvious over Koksal et al in view of Lang in view of Ogawa et al and further in view of Weitz et al.
Koksal et al additionally teaches;
The claimed “wherein the microfluidic chip is formed of a polymer” has been read on the taught ([0107], “…substrate layer 362 may be formed of [...] a polymer, etc. and microfluidic channel 330 may be patterned therein.”).
With regards to claim 3, the system of claim 1 is obvious over Koksal et al in view of Lang in view of Ogawa et al and further in view of Weitz et al.
Koksal et al additionally teaches;
The claimed “wherein the microfluidic chip is formed of glass” has been read on the taught ([0107], “…substrate layer 362 may be formed of [...] a glass, [...], etc. and microfluidic channel 330 may be patterned therein. ”).
With regards to claim 4, the system of claim 1 is obvious over Koksal et al in view of Lang in view of Ogawa et al and further in view of Weitz et al.
Koksal et al additionally teaches the following;
The claimed “wherein at least one of the plurality of layers seals an open portion of the microfluidic channel (Figure 8B, substrate layer 363, channel 330; [0111], “...a second thin substrate layer 363 may be used as a cover layer to form the enclosed channel 330.”; See also Figure 8D).
With regards to claim 5, the system of claim 1 is obvious over Koksal et al in view of Lang in view of Ogawa et al and further in view of Weitz et al.
Koksal et al additionally teaches the following;
The claimed “wherein the piezoelectric substrate is formed at least in part of lithium niobate” has been read on the taught ([0006], “As a non-limiting example, a piezoelectric substrate may be formed of a ferroelectric material such as lithium niobate. ”).
With regards to claim 6, the system of claim 1 is obvious over Koksal et al in view of Lang in view of Ogawa et al and further in view of Weitz et al.
Koksal et al additionally teaches the following;
The claimed “wherein the plurality of layers match the acoustic impedance of the piezoelectric substrate to reduce reflection of acoustic waves at interfaces between the plurality layers and the piezoelectric substrate” has been read on the taught ([0087], “According to other aspects, it may be desirable to match acoustic impedances of adjacent materials transmitting acoustic energy from one material layer to the other. This impedance matching may be more important than minimizing acoustic transmission losses.”; [0087] lays out in detail materials which may be acoustically transmissive, dampening, or reflective.).
With regards to claim 7, the system of claim 1 is obvious over Koksal et al in view of Lang in view of Ogawa et al and further in view of Weitz et al.
Koksal et al additionally teaches the following;
The claimed “wherein at least one of the plurality of layers includes an acoustic gel” has been read on the taught ([0112], “Coupling agent 367 may be formed as an intermediate liquid, gel, solid polymer, epoxy, or other acoustically-transmissive layer.”).
With regards to claim 8, the system of claim 1 is obvious over Koksal et al in view of Lang in view of Ogawa et al and further in view of Weitz et al.
Koksal et al additionally teaches the following;
The claimed “wherein the interdigital transducer is a component that can be separated or removed from the microfluidic chip” has been read on the taught ([0133], “As one option, the microfluidic chip 320 may be removably operatively engaged with the surface acoustic wave generator assembly 505 on the instrument 620.”; [0134], “The surface acoustic wave generator assembly 505 includes one or more surface acoustic wave generators 510. In this particular embodiment, surface acoustic wave generator assembly 505 includes a single tapered IDT 512 for generating surface acoustic waves...”).
With regards to claim 10, the system of claim 1 is obvious over Koksal et al in view of Lang in view of Ogawa et al and further in view of Weitz et al.
Lang additionally teaches the following;
The claimed “a bonding layer disposed between the piezoelectric substrate and the plurality of layers” has been read on the taught (Figure 1, piezoelectric transducer element 114, connecting element 118, matching body 116; [0029], “The matching body 116 can be directly or indirectly with the piezoelectric transducer element 114 be connected. In the illustrated embodiment, the matching body 116 indirectly with the piezoelectric transducer element 114 by at least one connecting element 118.”; [0037], “The piezoelectric transducer element 114 is usually about the at least one optional connector 118 with the fitting body 116 connected, this at least one connecting element 118 For example, may comprise at least one bonding layer, for example an adhesive and in particular an epoxy resin.”; Connecting element 118, which may comprise at least one bonding layer such as an adhesive or an epoxy resin has been read on the bonding layer. Figure 1 clearly shows layer 118 disposed between the piezoelectric substrate and one of the plurality of layers, such as layer 116.).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to further modify the microfluidic system including a piezoelectric substrate and a plurality of layers as taught by Koksal et al in view of Lang in view of Ogawa et al in view of Weitz et al with the bonding layers disposed between the piezoelectric substrate and one of the plurality of layers as taught by Lang, for the benefit of protecting the piezoelectric substrate against thermomechanical strain as taught by Lang ([0037], “For example, this may be the connecting element 118 according to DE 10 2008 055 123 B3 be designed so that this is the piezoelectric transducer element 114 protects against thermomechanical strain.”).
With regards to claim 22, the system of claim 1 is obvious over Koksal et al in view of Lang in view of Ogawa et al and further in view of Weitz et al.
Ogawa et al additionally teaches;
The claimed “wherein the plurality of layers have the different acoustic impedance properties to provide a step-wise or gradient transition from a starting acoustic impedance to a final acoustic impedance” has been read on the taught ([0082], “…the acoustic matching layers 17A include first acoustic matching layers 18A (conductive members) and second acoustic matching layers 19A, which are made of different materials, such that the acoustic impedances change stepwise from the piezoelectric elements 15A toward the human body.”; The impedance of the piezoelectric element reads on a starting acoustic impedance. The impedance of a human body reads on a final acoustic impedance..).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the device including a coupling layer as taught by Koksal et al in view of Lang in view of Ogawa et al in view of Weitz et al with the plurality of layers, each having a different acoustic impedance as taught by Ogawa et al. According to MPEP 2143(I)(C), use of a known technique to improve similar devices in the same way may be prima facie obvious. In the case of the instant invention, the prior art of Koksal et al in view of Lang contains a “base” device of an acoustic wave generator with an impedance matching layer coupling to a test surface. The prior art of Ogawa et al contains a “comparable” device which has been improved in the same way as the invention; an acoustic wave generator that has been improved with multiple impedance matching layers coupling towards a testing surface, each layer having a different acoustic impedance. One of ordinary skill in the art could have applied the technique of multiple layers in the same way to the “base” device, for the predictable result of more efficiently transmitting acoustic waves from the starting substrate to the testing surface.
With regards to claim 23, the system of claim 22 is obvious over Koksal et al in view of Lang in view of Ogawa et al and further in view of Weitz et al.
Ogawa et al additionally teaches;
The claimed “wherein the starting acoustic impedance corresponds to an impedance of the piezoelectric substrate and the final acoustic impedance corresponds to an impedance of a fluid in the microfluidic channel” has been read on the taught ([0082], “…the acoustic matching layers 17A include first acoustic matching layers 18A (conductive members) and second acoustic matching layers 19A, which are made of different materials, such that the acoustic impedances change stepwise from the piezoelectric elements 15A toward the human body.”).
Ogawa et al teaches the application of sonic elements in an ultrasonic probe, within the field of endeavor of imaging the human body (see [0005] and [0006]). However, Ogawa et al’s teaching regarding the stepwise change of the impedance layer is clear; the impedance matching starts closest to the generating element, and moves towards matching with the testing element.
One of ordinary skill in the art before the effective filing date of the claimed invention would be able to recognize that the human body being tested in Ogawa et al is analogous to the fluid in the microfluidic chip taught by Koksal et al, and apply the technique taught by Ogawa et al accordingly. This is especially true in light of Koksal et al [0087], which teaches that matching the acoustic impedance values of adjacent materials allows transmission of acoustic energy from one material to another, and Koksal [0137], which teaches that efficient transmission of acoustic energy is desirable.
According to MPEP 2143(I)(C), use of a known technique to improve similar devices in the same way may be prima facie obvious. In the case of the instant invention, the prior art of Koksal et al in view of Lang in view of Ogawa et al in view of Weitz et al contains a “base” device of an acoustic wave generator with an impedance matching layer coupling to a test surface. The prior art of Ogawa et al contains a “comparable” device which has been improved in the same way as the invention; an acoustic wave generator that has been improved with multiple impedance matching layers coupling towards a testing surface, each layer having a different acoustic impedance. One of ordinary skill in the art could have applied the technique of multiple layers in the same way to the “base” device, for the predictable result of more efficiently transmitting acoustic waves from the starting substrate to the testing surface.
With regards to claim 24, the system of claim 1 is obvious over Koksal et al in view of Lang in view of Ogawa et al and further in view of Weitz et al.
Weitz et al further teaches;
The claimed “the IDT being tapered, the tapered IDT including a first side and an opposing second side, the first side extending closer to the microfluidic channel than the opposing second side; at least a portion of the first side is overlaid by the plurality of layers; and the surrounding air is disposed over the second side” has been read on the taught ([0085], “…a tapered interdigital transducer (IDT) can generate surface acoustic waves that can actuate particles, cells, or other species. […] The IDT is positioned directly adjacent to the microfluidic device's sorting channel to increase the amount of power that gets transferred to the liquid, by minimizing the distance the SAW must travel before it refracts into the liquid in the channel, as shown in FIG. 1A. The fingers of the IDT are situated beneath an air gap, to prevent the power carried by the SAW from leaking into the device prematurely.”)
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the device of Koksal et al in view of Lang in view of Ogawa et al and further in view of Weitz et al with the tapered IDT positioned towards a channel and an air gap as taught by Weitz et al, for the predictable benefit of directing a specified wavelength through the aperture of the transducer while preventing resonance leaking through the channel prematurely, as taught by Weitz et al ([0085], “In the tapered IDT design, a range of frequencies can excite SAWs, at different positions along the transducer, because the resonant wavelength, defined by the pitch of the electrodes, varies along the transducer. The slope at which the IDT tapers determines the aperture of the SAW, by limiting the area of the transducer in which a given frequency resonates. The IDT is positioned directly adjacent to the microfluidic device's sorting channel to increase the amount of power that gets transferred to the liquid, by minimizing the distance the SAW must travel before it refracts into the liquid in the channel, as shown in FIG. 1A. The fingers of the IDT are situated beneath an air gap, to prevent the power carried by the SAW from leaking into the device prematurely.”).
With regards to claim 26, the system of claim 1 is obvious over Koksal et al in view of Lang in view of Ogawa et al and further in view of Weitz et al.
Koksal et al further teaches;
The claimed “wherein the piezoelectric substrate is formed at least in part of lithium niobate” has been read on the taught ([0006], “As a non-limiting example, a piezoelectric substrate may be formed of a ferroelectric material such as lithium niobate.”);
The claimed “the microfluidic chip is formed of a glass” has been read on the taught ([0087], “The substrate layers 360 (including layers 362, 363, 364, 366) of the microfluidic chip 320 may be glass…”);
Koksal et al additionally teaches that the layers may be configured to transmit acoustic waves (see [0112]).
Ogawa et al additionally teaches;
The claimed “wherein the starting acoustic impedance corresponds to an impedance of the piezoelectric substrate and the final acoustic impedance corresponds to an impedance of a fluid in the microfluidic channel” has been read on the taught ([0082], “…the acoustic matching layers 17A include first acoustic matching layers 18A (conductive members) and second acoustic matching layers 19A, which are made of different materials, such that the acoustic impedances change stepwise from the piezoelectric elements 15A toward the human body.”).
Ogawa et al teaches the application of sonic elements in an ultrasonic probe, within the field of endeavor of imaging the human body (see [0005] and [0006]). However, Ogawa et al’s teaching regarding the stepwise change of the impedance layer is clear; the impedance matching starts closest to the generating element, and moves towards matching with the testing element.
One of ordinary skill in the art before the effective filing date of the claimed invention would be able to recognize that the human body being tested in Ogawa et al is analogous to the fluid in the microfluidic chip taught by Koksal et al, and apply the technique taught by Ogawa et al accordingly. This is especially true in light of Koksal et al [0087], which teaches that matching the acoustic impedance values of adjacent materials allows transmission of acoustic energy from one material to another, and Koksal [0137], which teaches that efficient transmission of acoustic energy is desirable.
According to MPEP 2143(I)(C), use of a known technique to improve similar devices in the same way may be prima facie obvious. In the case of the instant invention, the prior art of Koksal et al in view of Lang in view of Ogawa et al in view of Weitz et al contains a “base” device of an acoustic wave generator with an impedance matching layer coupling to a test surface. The prior art of Ogawa et al contains a “comparable” device which has been improved in the same way as the invention; an acoustic wave generator that has been improved with multiple impedance matching layers coupling towards a testing surface, each layer having a different acoustic impedance. One of ordinary skill in the art could have applied the technique of multiple layers in the same way to the “base” device, for the predictable result of more efficiently transmitting acoustic waves from the starting substrate to the testing surface.
Claim 11 is rejected under 35 U.S.C. 103 as being unpatentable over Koksal et al (US 20180214874 A1) in view of Lang (DE 102012207873 A1) in view of Ogawa et al (US 20050261590 A1) and further in view of Weitz et al (US 20180257076 A1) as applied to claim 10 above, and further in view of Rivas et al (US 20170227497 A1, cited on PTO-892 submitted 12 May 2025).
With regards to claim 11, the system of claim 10 is obvious over Koksal et al in view of Lang in view of Ogawa et al and further in view of Weitz et al.
However, this combination fails to teach wherein the bonding layer is in a range of 50 to 100 nanometers.
In the analogous art of fluidic devices incorporating acoustic wave resonator, Rivas et al teaches the following:
The claimed “a bonding layer disposed between the piezoelectric substrate and the at least one of the plurality of layers” has been read on the taught (Figure 2, hermeticity layer 32; [0063], “... a piezoelectric material 22 and a top side electrode 28 overlaid with a hermeticity layer 32, an interface layer 34, a self-assembled monolayer (SAM) 36...”);
The claimed “wherein a thickness of the bonding layer is in a range of 50 to 100 nanometers” has been read on the taught ([0068], “If ALD is used for deposition of a hermeticity layer, then in certain embodiments a hermeticity layer may include a thickness in a range of from about 10 nm to about 25 nm. In certain embodiments, hermeticity layer thickness is about 15 nm, or from about 12 nm to about 18 nm. Conversely, if another process such as chemical vapor deposition is used, then a hermeticity layer may include a thickness in a range of from about 80 nm to about 150 nm or more, or in a range of from about 80 nm to about 120 nm. Considering both of the foregoing processes, hermeticity layer thicknesses may range from about 5 nm to about 150 nm.”).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the microfluidics system of claim 10 with the bonding layer in a range of 50 to 100 nanometers as taught by Rivas et al, in order to achieve a bonding layer thickness which provides adequate coverage for protection of the electrodes, without damping acoustic vibrations ([0068], “Moreover, ALD is capable of forming uniformly thin layers that provide relatively little damping of acoustic vibrations that would otherwise result in degraded device performance. Adequacy of coverage is important for a hermeticity layer (if present) to avoid corrosion of the underlying electrode.”).
Claim 12 is rejected under 35 U.S.C. 103 as being unpatentable over Koksal et al (US 20180214874 A1) in view of Lang (DE 102012207873 A1) in view of Ogawa et al (US 20050261590 A1) and further in view of Weitz et al (US 20180257076 A1) as applied to claim 10 above, and further in view of Rivas et al (US 20170227497 A1), as evidenced by Esro et al (Esro M, Kolosov O, Jones PJ, Milne WI, and Adamopoulos G. "Structural and Electrical Characterization of SiO2 Gate Dielectrics Deposited from Solutions at Moderate Temperatures in Air." ACS Applied Materials & Interfaces. 2017; 9(1): 529-536, cited on PTO-892 submitted 12 May 2025 and attached alongside that submission).
With regards to claim 12, the system of claim 10 is obvious over Koksal et al in view of Lang in view of Ogawa et al and further in view of Weitz et al.
However, this combination fails to teach wherein the bonding layer includes silicon dioxide.
In the analogous art of fluidic devices incorporating acoustic wave resonator, Rivas et al teaches the following:
The claimed “a bonding layer disposed between the piezoelectric substrate and at least one of the plurality of layers” has been read on the taught (Figure 2, hermeticity layer 32; [0063], “... a piezoelectric material 22 and a top side electrode 28 overlaid with a hermeticity layer 32, an interface layer 34, a self-assembled monolayer (SAM) 36...”);
The claimed “wherein the bonding layer includes silicon dioxide” has been read on the taught ([0069], “If provided, a hermeticity layer may include an oxide...” Silicon dioxide is an oxide.)
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the microfluidics system of Koksal et al in view of Lang to include the bonding layer including silicon dioxide as taught by Rivas et al in order to protect the electrode with a resistive, dielectric material (Rivas et al, [0060], “Various layers may be arranged [...]such as: a hermeticity layer (e.g., to protect the top side electrode from corrosion in a liquid environment)...”; Rivas and Gustafson, [0067], “If provided, a hermeticity layer preferably includes a dielectric material...”; Non-patent literature Esro et al, cited on the PTO-892 and attached with this office action, evidences the desirability of silicon dioxide as read on the taught (Section 1. Introduction, paragraph 1, “Despite the numerous dielectrics that have recently been developed, silicon dioxide (SiO2,) still remains the most common dielectric material used in the microelectronics field. The outstanding properties of SiO2, [include] excellent dielectric strength (=107 V/cm), high resistivity (=1015 ohm)...”).
Claim 21 is rejected under 35 U.S.C. 103 as being unpatentable over Koksal et al (US 20180214874 A1) in view of Lang (DE 102012207873 A1) in view of Ogawa et al (US 20050261590 A1) and further in view of Weitz et al (US 20180257076 A1) as applied to claim 1 above, and further in view of Teng et al (US 20180056340 A1, cited on PTO-892 submitted 12 May 2025), as evidenced by Rathod (Rathod VT. “A Review of Acoustic Impedance Matching Techniques for Piezoelectric Sensors and Transducers.” Sensors. 2020; 20(14):4051, cited on the IDS submitted 17 March 2022).
With regards to claim 21, the system of claim 1 is obvious over Koksal et al in view of Lang in view of Ogawa et al and further in view of Weitz et al.
Lang additionally teaches that it may be desirable for the plurality of layers to have a thickness of lambda / 4, which has been read on the taught ([0022], “By means of the present invention, ultrasound transducers with electromechanical transducer elements can accordingly be produced which have an open-pored and thus acoustically favorable matching body, for example at least one open-pore lambda-quarter impedance matching layer.”; Additionally, see [0035]).
However, this combination fails to teach wherein the thickness of the plurality of layers equals (n+1)*λ/4, where n is an integer number and λ is a wavelength of an acoustic wave.
In the analogous art of multilayer devices which generate acoustic waves using piezoelectric materials, Teng et al teaches;
“A piezoelectric material which generates acoustic waves” has been read on the taught (Figure 1, piezoelectric material 14; [0012], “wherein, the ultrasonic/megasonic generator comprises a piezoelectric material connected to at least one signal source outside the cleaning unit for receiving an electrical signal output from the at least one signal source and generating an ultrasonic/megasonic wave…”; [0054], “The ultrasonic/megasonic generator can be an ultrasonic/megasonic generator based on a piezoelectric material. In the present embodiment, the ultrasonic/megasonic generator includes a piezoelectric material 14…”);
“A layer configured to transmit acoustic waves” has been read on the taught (Figure 1, coupling layer 20; [0054], “…the ultrasonic/megasonic generator includes a piezoelectric material 14 and a coupling layer 20 which are closely contact with each other in the vertical direction.”);
Wherein the thickness of the layer equals (n+1)*1/4, where n is an integer number and X is a wavelength of an acoustic wave” has been read on the taught ([0057], “The coupling layer 20 has a thickness approximately equaling to an integer number plus one-quarter wavelengths of the ultrasonic/megasonic wave generated by the piezoelectric material.”).
In the analogous art of piezoelectric transducers, Rathod evidences the following;
“Matching layers with an integer number plus one-quarter acoustic thickness” has been read on the taught (Section 2. Acoustic Matching Tools and Methods, “The matching configurations available for bulk wave transducers are half-wavelength (λ/2), single quarter-wavelength (λ/4), one-eighths λ/8, and similar configurations to λ/4 such as (n + 1)λ/4, stacks of λ/4 layers, and a stack of very thin matching layers whose total acoustic thickness is λ/4.”);
Rathod additionally teaches the purpose of such thickness with regards to the wavelength’s periodicity, which has been read on the taught (Section 2.1. Traditional Quarter Wavelength Matching Method, “A quarter-wavelength matching layer ensures that all transmitting reverberations have the same phase, thereby ensuring constructive and destructive interference.”).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the system including a piezoelectric transducer and the plurality of coupling layers as taught by Koksal et al in view of Lang in view of Ogawa et al with the total coupling layer thickness as taught by Teng et al. According to MPEP 2143(I)(D), applying a known technique to a known device ready for improvement to yield predictable results may support a prima facie case of obviousness. In the case of the instant application, Teng et al teaches a base device (a piezoelectric transducer for generating acoustic waves), and applies the known technique of using a layer with a thickness approximately equaling an integer number plus one-quarter wavelengths. As evidenced by Rathod, one of ordinary skill in the art would have recognized that applying the known technique of (n + 1)λ/4 layers would have had the predictable result of ensuring that all transmitted reverberations are aligned in phase, resulting in an improved system.
Claim 25 is rejected under 35 U.S.C. 103 as being unpatentable over Koksal et al (US 20180214874 A1) in view of Lang (DE 102012207873 A1) in view of Ogawa et al (US 20050261590 A1) and further in view of Weitz et al (US 20180257076 A1) as applied to claim 1 above, and further in view of Lipkens et al (US 9670477 B2).
With regards to claim 25, the system of claim 1 is obvious over Koksal et al in view of Lang in view of Ogawa et al and further in view of Weitz et al.
However, this combination does not explicitly disclose wherein the different acoustic impedance properties are operative to couple the transmitted acoustic waves into the microfluidic channel with a Rayleigh angle in a range of about 22 to 90 degrees.
In the analogous art of acoustic devices for particle manipulation, Lipkens et al teaches;
The claimed “wherein the different acoustic impedance properties are operative to couple the transmitted acoustic waves into the microfluidic channel with a Rayleigh angle in a range of about 22 to 90 degrees” has been read on the taught (Abstract, “The angled acoustic standing wave can be oriented at an angle of about 20° to about 70° relative to the direction of mean flow through the flow chamber to deflect, collect, differentiate, or fractionate the materials from the fluid .”).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the device of Koksal et al in view of Lang in view of Ogawa et al and further in view of Weitz et al, with the angling of the standing wave as taught by Lipkens et al, for the predictable benefit of controlling the separation of particles, as taught by Lipkens et al (Column 9, line 27, “The angled acoustic standing waves can be used to separate or fractionate particles in the fluid by size, density, speed of sound, or shape. […] The deflection of the particles by the standing wave can also be controlled or amplified by the […] the angle of the acoustic field…”).
Claims 27 and 28 are rejected under 35 U.S.C. 103 as being unpatentable over Koksal et al (US 20180214874 A1) in view of Lang (DE 102012207873 A1) in view of Ogawa et al (US 20050261590 A1) and further in view of Weitz et al (US 20180257076 A1) as applied to claim 10 above, and further in view of Lenshof et al (Lenshof A, Evander M, Laurell T, and Nilsson J. “Acoustofluidics 5: Building microfluidic acoustic resonators.” Lab Chip, 2012, 12, 684.).
With regards to claim 27, the system of claim 26 is obvious over Koksal et al in view of Lang in view of Ogawa et al and further in view of Weitz et al.
Koksal et al further teaches the use of PDMS, a flexible material, in the construction of the device (see [0087]).
Weitz et al specifically notes that all components of the device may be flexible, as read on the taught ([0075], “In one embodiment, various components of the invention are fabricated from polymeric and/or flexible and/or elastomeric materials…”);
Weitz et al further supports the examiner’s claim that PDMS is a flexible material, as read on the taught ([0076], “Also, silicone polymers, such as PDMS, can be elastomeric and thus may be useful for forming very small features with relatively high aspect ratios, necessary in certain embodiments of the invention.”).
While Ogawa et al teaches a method of creating acoustic matching layers, the layers taught by Ogawa et al are not flexible. Accordingly, a further reference, Lenshof et al, is provided.
In the analogous art of microfluidic acoustic focusing devices, Lenshof et al teaches;
Wherein a matching layer is arranged according to stepwise acoustic impedance, as has been read on the taught (Page 687, column 1, paragraph 3, “To avoid acoustic losses due to reflection, the acoustic impedances of two adjacent layers should be carefully matched so that the acoustic energy density in the fluidic layer is maximised. For instance, when designing the matching layer, the characteristic acoustic impedance of the layer should be lower than that of the transducer but higher than the material comprising the fluidic cavity.”)
Wherein the matching layer is flexible PDMS (see Table 1).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the device with multiple stepwise acoustic matching layers as taught by Koksal et al in view of Lang in view of Ogawa et al in view of Weitz et al, with the flexible matching layers as taught by Lenshof et al. According to MPEP 2143(I)(C), use of a known technique to improve similar devices in the same way may be prima facie obvious. In the case of the instant invention, the prior art of Koksal et al in view of Lang in view of Ogawa et al and further in view of Weitz et al contains a “base” device of an acoustic wave generator with an impedance matching layer coupling to a test surface. The prior art of Lenshof et al contains a “comparable” device which has been improved in the same way as the invention; an acoustic wave generator that has been improved with a flexible impedance matching layer. One of ordinary skill in the art could have applied the technique of multiple layers in the same way to the “base” device, for the predictable result of more efficiently transmitting acoustic waves from the starting substrate to the testing surface.
With regards to claim 28, the system of claim 26 is obvious over Koksal et al in view of Lang in view of Ogawa et al in view of Weitz et al.
However, this combination does not explicitly disclose wherein the matching layer is composed of PDMS.
In the analogous art of microfluidic acoustic focusing devices, Lenshof et al teaches;
The claimed “wherein the plurality of layers includes a layer formed of one of: polydimethylsiloxane” has been read on the taught (See Table 1, line 9).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the device with multiple stepwise acoustic matching layers as taught by Koksal et al in view of Lang in view of Ogawa et al in view of Weitz et al, with the PDMS matching layer as taught by Lenshof et al. According to MPEP 2143(I)(C), use of a known technique to improve similar devices in the same way may be prima facie obvious. In the case of the instant invention, the prior art of Koksal et al in view of Lang in view of Ogawa et al and further in view of Weitz et al contains a “base” device of an acoustic wave generator with an impedance matching layer coupling to a test surface. The prior art of Lenshof et al contains a “comparable” device which has been improved in the same way as the invention; an acoustic wave generator that has been improved with a PDMS matching layer. One of ordinary skill in the art could have applied the technique of multiple layers in the same way to the “base” device, for the predictable result of creating as device using a loc cost and easily fabricated polymer.
Allowable Subject Matter
Claim 29 is objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims.
The following is a statement of reasons for the indication of allowable subject matter:
The use of impedance matching layers is well known across applications where the manipulation of acoustic energy is desired. An impedance matching layer with an impedance gradient, to ease the transition from one substance to another and minimize reflection is likewise known in the art, as discussed in the rejections of claim 22, for example.
However, recent improvements have been seen in the fabrication of the matching layers. Guillermic R-M. et al (Guillerimic R-M., Lanoy M, Strybulevych A, Page J.H. “A PDMS-based broadband acoustic impedance matched material for underwater applications.” Ultrasonics 94 (2019) 152-157) teaches tuning the acoustic impedance of a material by dispersing particles with one acoustic impedance within a matrix having a different acoustic impedance. Chaggares et al (US 20070205698 A1) teaches the use of multiple matching layers composed of multiple materials for an ultrasonic probe.
However, the combined limitations of claim 29;
encompassing a microfluidic chip including a microfluidic channel; an interdigital transducer (IDT) including electrodes and a piezoelectric substrate; and a plurality of layers configured to transmit acoustic waves, the plurality of layers disposed between the microfluidic chip and the piezoelectric substrate, each of the plurality of layers having a different acoustic impedance property, the IDT generating surface acoustic waves that couple into the microfluidic channel through the plurality of layers, the plurality layers having a thickness in a range from 10 micrometers to 250 micrometers, at least one of the plurality of layers overlying at least a portion of the electrodes of the IDT such that surrounding air is disposed over another portion of the electrodes of the IDT, and further wherein the piezoelectric substrate is formed at least in part of lithium niobate; the microfluidic chip is formed of a glass; and the different acoustic impedance properties of the plurality of layers allow a gradient transition from an acoustic impedance of the piezoelectric substrate to an acoustic impedance of fluid in the microfluidic channel, and further wherein the plurality of layers includes a layer formed of a mixture of high acoustic impedance materials and low acoustic impedance materials;
These combined limitations are such that one of ordinary skill in the art would not be able to form the combination based on the teaching of ultrasonic devices, given the complication of managing multiple layers with different impedance, wherein one of the plurality of layers is formed of a mixture of high acoustic impedance materials and low acoustic impedance materials.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
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/ALISON CLAIRE GERHARD/Examiner, Art Unit 1797 /LYLE ALEXANDER/Supervisory Patent Examiner, Art Unit 1797
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